Prices going up is what you see. Money going down is what is happening.
Inflation is the general price level rising over time, so that one unit of money buys less than it did. Too much money chasing too few things is one road there, and history keeps walking it: silver arriving from a mountain in the Andes, a Roman coin quietly stripped of its silver content, a deposit written into an account when a bank approves a loan. It is not the only road. Demand, wages, expectations, taxes, energy prices and a supply chain that breaks can all push the level up on their own.
It cannot be measured directly, because money is the ruler that is shrinking. So statistical agencies price a basket instead: a representative set of goods and services, checked repeatedly. In the United States tens of thousands of prices are collected every month and weighted by what households actually spend.
That published number is an average, so your personal inflation rate is almost certainly different from it. Most central banks deliberately target 2% a year rather than zero.